Problem: There are $5$ birds sitting on a tree branch. $2$ are robins and the rest are blue jays. Complete the number sentences to find how many of the birds are blue jays. $5$ birds in all $- \,2$ robins $= $
Explanation: $5$ can be separated into two parts: ${2}$ and $?$ We can use subtraction to find the missing part: $5 - {2} = 3$ We can also think about how much more can be added to ${2}$ to get $5$ : ${2} + 3 = 5$ The answer $ 5 - {2} = 3 $ ${2} + 3 = 5$